1. Field of the Invention
The present invention relates to an electronic musical instrument in which the music or score displayed on a screen is sequentially subjected to page feed as a musical performance advances.
2. Description of the Related Art
Hitherto, there is known an electronic musical instrument in which music is displayed on a screen, and the music displayed on the screen is sequentially subjected to page feed as a musical performance advances, that is, the page feed of so-called electronic music is carried out following a progression of the performance. According to such an electronic musical instrument, when the page feed of the music displayed on the screen is carried out, there is provided such a control that when the performance of the music now displayed is terminated, the music displayed on the screen is once erased in its entirety, and then music of the new page is displayed. However, this scheme is associated with such a problem that immediately before the page feed of the music displayed is carried out, a performer cannot know music information as to the successive performance. In order to solve this problem, in Japanese Patent Application Laid Open Gazette (Kokai) Sho. 59-5288, there is proposed technology such that a field (screen) is partitioned into two parts, that is, an upper stave and the lower stave, music is displayed on the upper stave and the lower stave, respectively, and in this condition, the music displayed on the stave associated with the termination of the performance is erased and the music of the successive page is displayed on the stave of concern. In this manner, music of mutually different pages is displayed on the upper stave and the lower stave, respectively.
However, such technology is associated with a problem that a display speed is slow, since there is adopted such a scheme that first the music displayed on the stave associated with the termination of the performance is erased once, and then the music of the successive page is displayed on the stave of concern.
Generally, in the event that image data representative of music information on the score is produced, in view of the fact that a large amount of memory is needed if image information associated with the overall field is maintained, there is provided such a processing that music information is encoded and stored, and when it is displayed, the encoded music information is developed. However, it is a great load for a CPU that the encoded music information is subjected to development processing to produce the image data as mentioned above. Thus, the conventional electronic musical instrument has been associated with a problem that in displaying the music on a screen, display speed is slow. Further, in the event that there is performed a partial page feed such that a part of the music of the successive page is displayed on a part of the music of the page now displayed, it happens in some cases that notes, symbols or the like to be displayed drop out depending upon the figure of the partial page feed. Taking into account the figure of the partial page feed and producing image data causes the development processing to be very complicated. Thus, the conventional electronic musical instrument has been associated with also a problem that a display speed becomes further slower.